1. Field of the Invention
Aspects of the present invention relate to an electrode-forming composition and a plasma display panel manufactured using the same, and more particularly, to an electrode-forming composition of which a composition ratio is optimized so as to protect an electrode against a migration effect and an edge-curl, as well as a plasma display panel manufactured using the same.
2. Description of the Related Art
As is well known, a plasma display panel (hereinafter referred to as “PDP”) is a display device that forms an image by using visible light beams of red (R), green (G), and blue (B) generated when vacuum ultra-violet (VUV) rays, which are emitted from plasma obtained through a gas discharge, excite a phosphor material.
With the PDP, the thickness of a very large screen with a diagonal greater than 60 inches can be minimized to less than 10 cm. Since the PDP is a self-emissive device like a CRT, distortion does not take place in terms of color reproduction capability and viewing angle. Further, the manufacturing process of the PDP is simpler than that of a liquid crystal display (LCD). Therefore, the PDP, having merits of high productivity and cost competitiveness, is highly expected to be used for television sets and industrial flat displays.
The structure of the PDP has been in development since 1970. A currently well-known structure thereof is an AC three-electrode surface discharge structure.
A PDP employing the AC three-electrode surface discharge structure is generally constructed such that pairs of display electrodes are formed on a front substrate with their surfaces facing the front substrate, and address electrodes are formed on the rear substrate spaced apart from the front substrate. A barrier rib is disposed between the front and rear substrates to define a plurality of discharge cells. The discharge cells are formed along positions where the display electrodes cross the address electrodes. Phosphor layers are formed inside the discharge cells, and a discharge gas is injected therein. The injected discharge gas produces a discharge within the discharge cells according to a voltage supplied through the above-mentioned electrodes. Ultra-violet rays generated by the discharge collide against the phosphor layers inside the discharge cells, thereby generating visible light.
In the PDP employing this structure, a discharge cell to be turned on and a discharge cell not to be turned on are selected by using the memory characteristic of wall charges. The selected discharge cell is discharged to display an image.
A PDP having a 42-inch diagonal screen size with resolution of XGA (1024×768) has recently become available in the market. Ultimately, there is a demand for a display device capable of displaying a Full-HD (high definition) image. In order for a PDP to display a Full-HD (1920×1080) image, a discharge cell has to be reduced in size to achieve that higher density. Accordingly, the width and pitch of the electrodes need to be more densely formed.
In general, the PDP includes an address electrode formed of silver (Ag) having high electric conductivity and that is relatively inexpensive. However, when the width of the electrodes and the space between them (pitch) is narrower in order to achieve the desired higher density, the electrodes may become electrically open or a short circuit may occur due to a migration effect occurring at the edges of neighboring electrodes. The migration effect may arise from various causes. In many cases, it is caused by chemical or physical problems stemming from external air and/or temperature. The external air and/or temperature eventually promote diffusion of the photosensitive silver electrode generally used for an electrode. This may electrically open the circuit between discharge and address electrodes or short circuit the electrodes by forming a bridge between two neighboring electrodes.
Thus, various attempts are underway to prevent defects with silver electrodes caused by the migration effect.
For example, there is a method in which electrodes where the migration effect occurs are treated with various air-proof/moisture-proof materials, and organic/non-organic foreign materials between the electrodes are removed as much as possible through cleansing and the like. When an electronic device having semiconductors and other electrode wires is used, instead of the highly responsive material of silver, an extremely expensive metal (e.g. gold, platinum, etc.) is used. Alternatively, a full solid solution of palladium (Pd) or the like is added with silver.
When a PDP generally including a silver electrode is used, in order to reduce electrode manufacturing operations and material costs, characteristics of the electrode itself have to be controlled so as to prevent the migration effect.
An address electrode is formed such that a photosensitive silver paste is applied on a rear substrate and is then dried to form an electrode layer, and the electrode layer is exposed and developed in such a way as to form patterns on the electrode.
However, in the process of forming this address electrode, if exposure and development processes are not properly controlled, an edge-curl may take place whereby both edges of the address electrode are curled up (see FIG. 6(a)).
The edge-curl may cause concentration of the discharge voltage that is supplied to the address electrode, and damage in the dielectric layer that covers the edge-curl during a gas discharge. Accordingly, product reliability decreases.